9TH EUROPEAN AIDS CONFERENCE (EACS)
1st EACS RESISTANCE & PHARMACOLOGY WORKSHOP

 October 25 - 29, 2003 Warsaw, Poland

6.2 Primary Infection

 F6/3 - INFLUENCE OF VIRAL LOAD ON THE TRANSMISSION OF DRUG-RESISTANT (DR) AND WILD TYPE (WT) HIV VARIANTS: COMPARISON OF RESISTANCE BETWEEN CHRONICALLY-INFECTED (CI) AND RECENTLY-INFECTED (RI) PATIENTS
* Routy J.P.1, Machouf N. (1,4), Brenner B.2, Thomas R. (1,3,4), Trottier B.4, Rouleau D.3, Côté P.4, Baril J.G.4, Tremblay C.3, LeBlanc R. (1,4), Edwardes M.1, Turner D.2, Sekaly R.P.5, Wainberg M.2
 
(1) McGill Health Centre,2 McGill University AIDS Centre, McGill University,3 Centre Hospitalier de l'Université de Montréal,4 Private Medical Clinics,5 Department of Microbiology and Immunology, University of Montreal, Montreal, Canada
 

Background: The relative transmissibility of wild type and DR variants is unknown. We assessed the influence of viral load on HIV transmission for WT and DR variants.

Methods: Since 1999, a retrospective analysis of CI patients followed in a large clinic (n=2650), representing 30% of the potential transmitters in Montreal was performed. The prevalence of DR transmission was estimated by genotypic analysis of recently-infected (RI) patients from the Montreal Primary-HIV-infection cohort (n=170).

Results: The proportion of untreated CI patients decreased by 4 % after 2001 and was similar for MSM and IDUs. Prevalence of RT mutations V118I, M184V/I and K103N increased (3 to 26%, 56 to 68% and 14 to 33% respectively) while most PI associated mutations remain similar over time. Prevalence of DR was compared in CI and RI patients, a 5 fold diminished transmission was estimated for M184V/I and D30N. These two mutations where associated respectively with a 0.7 and 0.8 log VL reduction when compared to WT. A mean of 1.4 log VL reduction was observed in CI patients up to 2001, which was chronologically associated with a decrease in DR prevalence in RI patients [17% (n=20/122) vs 4% (n=2/48) (P<0.05)].

Conclusion: The decrease in VL observed in CI patients corroborates the decrease in DR transmission despite an augmentation of DR prevalence in the population of potential transmitters. Presence of mutations conferring lower VL looks to be less transmissible. Transmission of WT or DR variants seems to occur only with individuals having high viral load (4 log).

Presenting Author: Dr Jean Pierre Routy, McGill University Health Centre, Chest Hospital, 3650 St-Urbain, Unité d'immunodéficience, 8ième étage, H2X 2P4, Montreal, Canada, Phone: 011-514-842-1231 -35883

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